Leetcode 118. Pascal's Triangle array (Yang Hui triangle)

118 Pascal ' s Triangle

Given numrows, generate the first numrows of Pascal ' s triangle.

For example, given numrows = 5,
Return

[1], [1,2,1], [1,3,3,1], [1,4,6,4,1]

Main topic:

Enter the number of rows to output as shown in the array. (Yang Hui triangle)

Ideas:

Use a double vector to handle the current line and the next line.

The code is as follows:

Class solution {public:    vector<vector<int>> generate (int  numrows)  {                 vector<vector<int>> result;        if ( numrows == 0)             return  result;        vector<int> curvec;         vector<int> nextVec;                 for (int i = 0;i < numrows; i++)         {             for (int j = 0;j<=i;j++)              {  &nbsP;             if (j == 0)                       nextvec.push_back (1);                 else                 {                     if (J >= curvec.size ())                          nextvec.push_ Back (Curvec[j-1]);                     else                         nextvec.push_back (Curvec[j] + curvec[j-1]);                 }             }             result.push_back (Nextvec);             Curvec.swap (Nextvec);             nextvec.clear ();         }        return  result;    }};

2016-08-12 09:34:50

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Leetcode 118. Pascal's Triangle array (Yang Hui triangle)